Personality has been found to significantly impact participation in psychological research in terms of time of participation (e.g., Aviv, Zelenski, Rallo, & Larsen, 2002), willingness to complete more difficult studies (e.g., Waite, Claffey, & Hillbrand, 1998), complete non-response (e.g., Pagan, Eaton, Turkheimer, & Oltmanns, 2006), and attrition (Norton, Booth, & Webster, 1976). The vast majority of this research was conducted on research paradigms typically used in social or personality psychology. This study sought to examine whether different personality factors predicted selection into and attrition from an intervention study when compared to a cognitive task or a one-time survey. Results suggest that personality did not predict self-selection into one of the three studies but that different personality traits predicted attrition based on the type of longitudinal study (i.e., task or intervention). Although personality factors did not predict self-selection, there were large differences in the number of participants in each study, suggesting that there is some sort of self-selection effect. The findings from this study are discussed in terms of their implications for research design and how we evaluate efficacy of interventions.